11 citations · 62 across the 21 of their papers we have counts for
22 papers
Universal bound on the Lyapunov spectrum of quantum master equations
Paolo Muratore-Ginanneschi, Gen Kimura, Frederik vom Ende +1
The spectral properties of positive maps are pivotal for understanding the dynamics of quantum systems interacting with their environment. Furthermore, central problems in quantum…
Simple Sufficient Criteria for Optimality of Entanglement Witnesses
Frederik vom Ende, Simon Cichy
If one wants to establish optimality of a given bipartite entanglement witness, the current standard approach is to check whether it has the spanning property. Although this is not…
Universal Bound on the Eigenvalues of 2-Positive Trace-Preserving Maps
Frederik vom Ende, Dariusz Chruściński, Gen Kimura +1
We prove an upper bound on the trace of any 2-positive, trace-preserving map in terms of its smallest eigenvalue. We show that this spectral bound is tight, and that 2-positivity i…
A universal constraint for relaxation rates for quantum Markov generators: complete positivity and beyond
Dariusz Chruściński, Frederik vom Ende, Gen Kimura +1
Relaxation rates are key characteristics of quantum processes, as they determine how quickly a quantum system thermalizes, equilibrates, decoheres, and dissipates. While they play…
Theory and Experimental Demonstration of Wigner Tomography of Unknown Unitary Quantum Gates
Amit Devra, Léo Van Damme, Frederik vom Ende +2
We investigate the tomography of unknown unitary quantum processes within the framework of a finite-dimensional Wigner-type representation. This representation provides a rich visu…
Generating Sets of Stochastic Matrices
Frederik vom Ende, Fereshte Shahbeigi
This paper introduces the concept of a generating set for stochastic matrices -- a subset of matrices whose repeated composition generates the entire set. Understanding such genera…
Almost All Quantum Channels Are Diagonalizable
Frederik vom Ende
We prove the statement "The collection of all elements of which have only simple eigenvalues is dense in " for different sets , including: all…
Understanding and Generalizing Unique Decompositions of Generators of Dynamical Semigroups
Frederik vom Ende
We generalize the result of Gorini, Kossakowski, and Sudarshan [J. Math. Phys. 17:821, 1976] that every generator of a quantum-dynamical semigroup decomposes uniquely into a closed…
Reachability, Coolability, and Stabilizability of Open Markovian Quantum Systems with Fast Unitary Control
Emanuel Malvetti, Frederik vom Ende, Gunther Dirr +1
Open Markovian quantum systems with fast and full Hamiltonian control can be reduced to an equivalent control system on the standard simplex modelling the dynamics of the eigenvalu…
Reduced Control Systems on Symmetric Lie Algebras
Emanuel Malvetti, Gunther Dirr, Frederik vom Ende +1
For a symmetric Lie algebra we consider a class of bilinear or more general control-affine systems on defined by a drift ve…
Exploring the Limits of Controlled Markovian Quantum Dynamics with Thermal Resources
Frederik vom Ende, Emanuel Malvetti, Gunther Dirr +1
Our aim is twofold: First, we rigorously analyse the generators of quantum-dynamical semigroups of thermodynamic processes. We characterise a wide class of GKSL-generators for quan…
From Kraus Operators to the Stinespring Form of Quantum Maps: An Alternative Construction for Infinite Dimensions
Frederik vom Ende
We present an alternative (constructive) proof of the statement that for every completely positive, trace-preserving map there exists an auxiliary Hilbert space in…
The Thermomajorization Polytope and Its Degeneracies
Frederik vom Ende, Emanuel Malvetti
Drawing inspiration from transportation theory, in this work we introduce the notions of "well-structured" and "stable" Gibbs states and we investigate their implications for quant…
Analytic, Differentiable and Measurable Diagonalizations in Symmetric Lie Algebras
Emanuel Malvetti, Gunther Dirr, Frederik vom Ende +1
We generalize several important results from the perturbation theory of linear operators to the setting of semisimple orthogonal symmetric Lie algebras. These Lie algebras provide…
Quantum-Dynamical Semigroups and the Church of the Larger Hilbert Space
Frederik vom Ende
In this work we investigate Stinespring dilations of quantum-dynamical semigroups, which are known to exist by means of a constructive proof given by Davies in the early 70s. We sh…
Which Bath-Hamiltonians Matter for Thermal Operations?
Frederik vom Ende
In this article we explore the set of thermal operations from a mathematical and topological point of view. First we introduce the concept of Hamiltonians with resonant spectrum wi…
Reachability in Controlled Markovian Quantum Systems: An Operator-Theoretic Approach
Frederik vom Ende
In quantum systems theory one of the fundamental problems boils down to: Given an initial state, which final states can be reached by the dynamic system in question? Formulated in…
On the Alberti-Uhlmann Condition for Unital Channels
Sagnik Chakraborty, Dariusz Chruściński, Gniewomir Sarbicki +1
We address the problem of existence of completely positive trace preserving (CPTP) maps between two sets of density matrices. We refine the result of Alberti and Uhlmann and derive…
Exploring the Limits of Open Quantum Dynamics I: Motivation, New Results from Toy Models to Applications
Thomas Schulte-Herbrüggen, Frederik vom Ende, Gunther Dirr
Which quantum states can be reached by controlling open Markovian -level quantum systems? Here, we address reachable sets of coherently controllable quantum systems with switcha…
Exploring the Limits of Open Quantum Dynamics II: Gibbs-Preserving Maps from the Perspective of Majorization
Frederik vom Ende
Motivated by reachability questions in coherently controlled open quantum systems coupled to a thermal bath, as well as recent progress in the field of thermo-/vector-majorization…
Reachable Sets from Toy Models to Controlled Markovian Quantum Systems
Gunther Dirr, Frederik vom Ende, Thomas Schulte-Herbrüggen
In the framework of bilinear control systems, we present reachable sets of coherently controllable open quantum systems with switchable coupling to a thermal bath of arbitrary temp…
Unitary Dilations of Discrete-Time Quantum-Dynamical Semigroups
Frederik vom Ende, Gunther Dirr
We show that the discrete-time evolution of an open quantum system generated by a single quantum channel can be embedded in the discrete-time evolution of an enlarged closed qu…